You can target 1 "Number C39" monster you control; equip this monster from your hand or your side of the field to that target. While this card is equipped to a monster, the equipped monster cannot be destroyed by battle. At the end of the Damage Step, if the equipped monster attacked a monster but did not destroy it by battle: The ATK of the attacked monster becomes 0, and if it does, the equipped monster can attack that monster once again.